The report, titled "In too deep: an investigation into debt and relationships" by relationship charity Relate, found 14 per cent of those with debt say they have kept it secret from a partner and 7 per cent of those with debt are currently hiding it.
Half of those surveyed said feeling ashamed is the most common reason why people hide their money problems, followed by 46 per cent who said they would be scared of their partner's reaction.
A third of those with hidden debts felt their partner had a different approach to money.
Helen Webb from CAP told Premier why she thinks people aren't being open about their finances.
She said: "I think people are struggling to learn how to talk to each other in general.
"It's not just within the relationship, but also outside of them because money is such a sensitive issue."
The report also highlighted how debt can cause conflict, mistrust and relationship breakdowns.
The survey of 4,700 UK adults found that one in six adults find meeting financial commitments a heavy burden.
- One in five has experienced the breakdown of a relationship with a partner where debt was either the main reason or a contributing factor.
- Nearly four in 10 said it has had a negative impact on their relationship with their partner.
- A quarter argues about money, debt, and/or other financial issues with their partner at least once a fortnight.
- Nearly one in 10 said they argue with their children once a week or more, which is three times as likely as those not currently in problem debt.
Webb told Premier discussing money needs to be normalised.
She said: "We want to encourage people to start talking about money, for it not to be kind of one of those closet conversations.
"We want people to just really try and find their confidence to start talking to their partner or their friends or their family about it."
The Treasury select committee recently launched an inquiry into household finances.
Listen to Helen Webb speaking with Premier's Marcus Jones here: